An electro-discharge machining (EDM) device that includes a housing, an erosion electrode, a ground electrode, and a dielectric inlet. The housing is configured to be positioned on a surface of a workpiece and proximal to a fastener to be eroded. The planar erosion electrode is positioned at least partially within the housing, with the erosion electrode being movable relative to the housing in a first axis. The first axis is substantially normal to a longitudinal axis of the fastener. The ground electrode is conductively connected to the fastener. The dielectric inlet is configured to deliver a dielectric fluid to a region between the erosion electrode and the fastener.